Thermionic-vacuum-tube circuits



Sept. 7 1926.

v H. TAYLOR THERMIONIC VACUUM TUBE CIRCUITS Filed May 29, 1923 gwvefnloz Albert H. Taylor @Hozucq Parental sept. 1, 192s.

` UNITED s TATi-:s

-1,599,104. PATENT OFFICE.'

' E. TAYLOR, OF WASHINGTON, DISTRICI.` OF COLUMBIA, ASSIGNOBTO WIBED ARAD'IO, mC., OF'NEWIYOB-K, N. Y., A CORPORATION OF DELAWRE.

i .'rHEBMIoNrc-VACUMTUBE/ CIRCUITS.

` Application led May 29, 1923. Serial No.` 642,277.

My invention relates toa system for voltage regulation in radio or similar apparatus employing vacuumy tubes supplied with alternating current for both yfilament and plate,'and the method of -accomplishing the same. i

An object of the invention is to `provide, a system wherein the filament voltage and plate voltage will remain substantially constant duringthe transmission ofsi-gnals or l other useof the apparatus when the load on the system is rapidly. changed.

In the operation ofy a vacuum tube radio set it isessential that t-hevoltage of the `filament andplate remain as near constant' as possible when signals are being transmit; j

ted.` Voltage variation, besides creating possible destructive conditions withinstheset, causes variations of wave length `which arel extremelyy objectionable. This variation ,is`v particularly Abad where'both the filamen-tand plate circuits are supplied from any altere.y

, abnormally high internal impedance. w

in voltagetwhen"signalsjfarea'being ftransr-ri .ffilamentlighting transformer, known as thenating current generator,y especially if*` thefrequency -of 'that generator is high, say from 300 to 100() cycles, because such maa. chines are frequentlyof the inductor type having `a*y rather large synchronous limpe'dfy ance. gerated-in the case Iof aircraft sets Where the generator must be of a minimum ,weight ffor.- a given out-put, Whichconstructionleads to:

This invention provides a Wayy of employing generators of very con's'iderablezinternal impedance" Without 'any sensible fluctuations t In` an "radio' set joperated'v by` vacuumy .tubes supp'lied' with alternating 1 currentat highl tension on the platesone or more'condenser-sl should be across *the terminals ioff-the "high tension winding of l the transformer nu fthe, supply circuit; These codensers are linown the plate clrcuit, and?j allow the' passage pf high frequentirrentsfsrouha thefhighim Hdingg l n ovides, 1 l:for

function. condenser@ are value suislellllyVA The difficulty isl still yfurther fexag-I he plate c1rcuit, balnd thereby-ffV adjusted to'l'wf high t0 Produce a ,spine-ef Theeifect of this current is to cause a rise in the generator voltage. To overexcite the field of a synchronous motor is to cause that synchronous motor to take a leading current. Conversely, a generator which is forced by c1rcu1t conditions to deliver a leading current will have its fields and therefore its l voltage raised. At the same time, the presence of capacity may be thought of as neutralizing the effect ofthe internal impedance.

constitute a load on the generatr, both as `to the filaments and the plates, there is sufficient effective resistance in 'the circuitl to prevent any dangerously large current flowing,`should the circuit be operated at or near resonance.v .It is best to operate the circuit a little beyond resonance nto get sufficient l v,rise of voltage from the effect of the leading current on the field 'to overcome voltage Since the vacuum tubes themselvesV 'losses due to either resistance or inductance in the generator and in the transformers aS- sociated with the generator for supplying filament and plate circuits.

'.Inasmuch as the load on any particular 'vacuum tube set will depend upon the type of antenna to which it is connected and uponthe resistance of that antenna, and `inasmuch as the amount of leading current required increases, moreor less, in proportion to the output load in orderto hold the voltages constant during operation of the set, there may be provided in addition to the ysuitable adjustment of the capacities already f mentioned, a further adjustment consisting :of y,an t additional primary winding on the .compensating winding, which winding is in serieson the low ktension side of the plate load,'that is, in 'series with the primarygof `thestep-up transformer supplying the pla es :This compensating Winding may be used to ,create additional flux in the core of the filamentflighting transformer and by suitably connecting the compensating Winding may be? made to either oppose or aid the flux y normallylcarried by the filament transformer. increasingif beyond#thebvaluesu:

This'. additional flux is, in general, not in phasewith the' principal flux of this trans- :1 former which fact does not in any wayin- Winding.y l

AS'The necessity for the function of a compensatingxwindino may be best illustrated bylan-fexample. luppose the set has been terfereswlth the action of the compensating operating on a wave 4length of 507 meters for which the antenna has a certain resistance. The operator then changes wave length to 600 meters where the antenna has a different resistance. It may not be convenient to change the capacities which producethe leading current and normally, if the capacities are just right for 507: meters, they will not be quite right for 600 meters on account of the dierent load on the'plate circuit. The voltage will'in this -case probably drop a little when the plate circuit is keyed, but this may be readily offset by adding a few turns to the compensating winding. It will be understood that this Winding is provided withtaps whichmake the number of turns adjustable. Or, if the set has been adjusted by suitably adjusting the condensers that produce the leading current for 600 meters without any turns in the ,compensatingqwinding and then the set is changed to 507 meters, where, in general, the resistance of the antenna will be higher and the plate load less, the voltage across the filaments may rise when the set is keyed. Ihis may be overcome by suitably connecting in a few turns of the compensating' winding by' means of adjusting switches in such a Way aSv to oppose the main` flux in the-filament lighting transformers.

With these and other objects inview, theY invention consists in the construction, .combinatlon, and arrangement of parts as will be hereinafter described.

In order to more clearly illustrate my invention, I shall now describe the preferred embodiment thereof lin connection with the accompanying drawing, in which the figure represents a schematic diagram of a circuit arrangement fulfilling the above objects.

Two transmitting vacuum tubes 1 and 2 are connected so that one tube operates on' one half of the alternations of the current and the other tube. onzthe opposite half, so

that both lobesof the current are rectified and deliver high frequency energy into the antenna. 4 It is to be understood, however, that the invention is not restricted to a set operating lon both lobes of the current, but works equally as well on one lobe. The

plates of these tubes are supplied with current from the secondary of a step-up transformer 3, a radio frequency choke 4 being placed in series with each plate and a radio frequency choke 5 in series with the grids and gridleak resistance 6. The plate coil is shown at, 7, the antenna coil at 8 and the back coupling condenser at 9. The'mid point, orneutral, of the high tension 'transformer secondary 3 is connected to the mid point,

.'-fyor neutral, of the step-down transformer l0 which lights the filaments andwhich has two radio frequency by-pass condensers -'11 and 12 across it. 'The compensating windin f 13 on the transformer 10 is adjustable in the number vof turns, and the sense of the direction of circulation of currents therethrough, and is in series with the primary-of 3. The generator is shown at 14. The two condensers 15 and 16 `placed across the two plates and acting as radio frequency bypasses for the plate coil have suitable adjustment to a value larger than ordinarily employed for by-pass purposes in radio sets, which provision permits a sufficient lead of the current to'obtain good voltage regulation. It will be understood that if it is desired to make these condensers adjustable the compensating winding can be dispensed with. It will also be understood that a very considerable variation of Evoltage may be corrected without abnormally large capacities at 15 and 16 by use of the compensating windingabove, but in this case it will have- `either adding or opposing as the case may be, the entire range of wave 4length of the set can be covered 'with good regulation. Frequently it is not desirable to increase the capacities 15 and 16 because they take consid-l erable current which4 has to flow to them through the radio frequency chokes. In such an event, a suitable capacity may be put 1 n at 17, shown in` dotted lines, across the primary of transformer 3 [and whose value is approximately equal VN2C2 where N is the turn ratio of the transformer. A capaclty placed across this primary will havethe same effect; it will have to be a much larger capacity Vbut on the other hand, the insulation resistance will be much less and, therefore, the total volume of the capacity, that is, thel total volume of dielectric used, will be approximately the same in both cases. The key 18 provides a means for making signals.

l It is understood that the above descrip- A Having fully described my invention,

what I desire to secure by Letters Patent 1s:-

1. A signal transmission system comprising in combination an electron tube oscillation generator system including a pair of interconnecting said electrodes, a source of alternating current for supplylng power to the circuits of said electron tubes, and a condenser located in the output circuits of each of said electron tubes, each condenser being of such value as to produce voltage regulation of the source of energy.

2. A signal transmission system comprising in combination a pair of electron tubes,

each having grid(` filament and lplate elec-4 trodes, input and output circuits interconnecting said electrodes, a .source of alternating current for supplying power to the circuits of said electron tubesa condenser located in each of said output circuits having such Value that voltage regulation of the source of energy is produced, and means for compensating for variations in the supply of energy from said source to the circuits of said electron tubes.

3. A signal transmission system comprising in combination a plurality of electronv tubes, each having grid, filament and plate elccitrodcs, input and output circuits interconnecting said electrodes, a source of alteri'iatingr currents independent 'transformer systems cach having primary and secondary circuits. one of said transformer systems being arranged to supply power to said lamentelcctrodes and the other of said transformer systems belng' arranged to supply power to said plate electrodes, the primary windings of each of said transformer systems being arranged in series with each other and in parallel with said source, a compensating winding in the transformer system which supplies power to said filament electrodes, and va connection between said compensating winding and the primary circuit of said other transformer system whereby variations in load `may be compensated by corresponding regulation of the voltage of said source.

4. A signal transmission system comprising in combination a pair of electron tubes connected in balanced relationship, input and output circuits connected with said electron tubes, a source of alternating current for supplying power to the circuits of said electron tubes, means interposed between said source and the circuits of said electron tubes for compensatingfor variations in the load, and means connected in the output circuits of each of said tubes for regulating the voltage of said source for maintaining the operation of said circuits constant.

5. A radio transmission system comprising in combination with an antenna ground circuit, a plurality of electron tubes each having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, a source of alternating current` a pair of transformer systems each having primary and secondary circuits, one ofsaid transformer systems being arranged for supplying power to said filament electrodes., and the other of said transformer systems beingarrangcd for supplying power to said Vplate electrodes.l the primary windings of said transformer systems being connected in series, and a shunt connection between opposite terminals of said primary ALBERT H. TAYLOR. 

